| Author | Message | ||
     Jason McCombs (Jasonmc) Member Username: Jasonmc Post Number: 101 Registered: 06-2003 |
hey guys teh other day i filled up the tank and left my gas cap on the bumper, drove off and was surprised when there was no gas cap thee the next time i filled, up.. duh.. i went to the gas station where i filled up and asked if they found any caps they had one that fit. i dont know if its actually mine or not. surprisingly enough i never really looked at the old gas cap when i filled up before. so heres my question. i know when i used to open my cap there would be a very loud and noticable air pressure release when i undid it. Is this a fuel system neccesity on the Discos or is it jsut a by product of the fule comsumption. the new as cap fits but i dont know if its my old one or not and if it doesnt allow the pressure to build up like before is this a problem? | ||
| marc olivares (Pugs) Member Username: Pugs Post Number: 170 Registered: 12-2002 |
yes this is a necessity, with discos as well as all obdII systems. the system requires a certain amount of pressure, and will build certain amounts of pressure. did you get a code when you drove off with out the cap? (you should have. it's the ecu detecting a leak in the purge system.) if you haven't gotten a code with the new cap you are most likely fine. i'm guessing that the tank is still relatively full and the pressure in the tank is lessend' by the fluid. i'm assuming that you replaced with the correct oem part? hope that helps? marc | ||
| Greg French (Gregfrench) Senior Member Username: Gregfrench Post Number: 589 Registered: 11-2002 |
The system is pressurized by the fuel pump, which is in the tank. The only part of the system that it is necessary to pressurize is from the pump to the injectors. As long as the pump is getting fuel, it shouldn't matter. The tank is pressurized due to expanding gasses inside. The hotter it is outside, the more pressure is built up. It will build up more if there is more room in the tank (like if it is half full or less). It shouldn't affect anything by not fitting tight, except maybe spilling. I went for a month or so with no cap, and was fine. You can get a new one at any major auto parts store. I could be wrong, but I don't think being an OBDII system has anything to do with it, as all of my vehicles have vented when I unscrewed the cap. | ||
| marc olivares (Pugs) Member Username: Pugs Post Number: 173 Registered: 12-2002 |
greg, your post is partially correct. yes the pump creates the pressure, yes the hotter the day the more expansion, but no,a tight fit is paramount. that why the cap indicates that you turn until tight and then click "x" times. In all OBDII systems the gasses are collected and recirculated into the engines combustion chamber as enert gas to keep exhaust gasses cool, there for lowering exhaust emissions. the fuel tanks are not vented into the atmosphere when the pressure increases which is why there is a pressure release when the cap is removed. you may not have noticed a difference in the vehicles immediate performance, but the long term affects can result in other emissions related issues. jason sorry, no this is not a fuel system requirement, it's an emissions related issue. marc | ||
| Hao Pang (Haohao) New Member Username: Haohao Post Number: 27 Registered: 06-2003 |
hehe, last time I lost my cap and my car died on the red light. Now I drilled a hole on my new cap and tired it with a string.  | ||
| thom mathie (Muskyman) Senior Member Username: Muskyman Post Number: 340 Registered: 11-2002 |
just go to wallmart get a new Stant cap and be done with it. for $9.95 why trust a unknown cap? if it throws a code you will spend $50 bucks at the dealer I'll bet | ||
| Ron L (Ronl) Member Username: Ronl Post Number: 172 Registered: 11-2002 |
Not having a cap on there is an emissions related issue. Evaporation is the problem, as a result the check engine light will come. Part of the OBD "keep em clean" rules. | ||
| Phil (Discoanywhere) Member Username: Discoanywhere Post Number: 80 Registered: 06-2003 |
Most Subaru Gas Caps fit! ...just thought I'd add this tid-bit of info.. I lost mine and used one that didn't fit well for about 3 months..didn't notice a thing? | ||
| Bill Ross (Billr) Member Username: Billr Post Number: 100 Registered: 11-2002 |
On my '94 a Stant cap for a Honda worked. I got mine at Walmart or Canadian Tire as I recall. | ||
| Greg French (Gregfrench) Senior Member Username: Gregfrench Post Number: 590 Registered: 11-2002 |
Marc...Never noticed the instructions on the cap. I just click it because I like the "feel" of it. Whether it makes a difference or not, he still needs to get one. | ||
| robert B. (Robertb) New Member Username: Robertb Post Number: 1 Registered: 09-2003 |
i am using one currently from a 96 s-10. now i have noticed fumes eminating inside the vehicle. will search out the correct one because i believe it matters. | ||
| thom mathie (Muskyman) Senior Member Username: Muskyman Post Number: 342 Registered: 11-2002 |
Stant is the maker of the factory Cap. just go to Wallmart pick up the little book,look up your year disco and then select the proper cap. thats really all you need to do. but if you want to drive around and keep checking in here day after day after day for a better cheaper solution then a brand new correct cap for $9.95 I'd bet there are some other things needing attention on your disco. | ||
| johnson kalawe (Mxjohn) New Member Username: Mxjohn Post Number: 10 Registered: 06-2003 |
lost my cap and picked one up a NAPA. |
